[date-time] converting milliseconds to time_duration - overflow issue
Hello, When I convert a (large) number of milliseconds to a time_duration, I noticed a truncation error. This is shown in the following example: BOOST_AUTO_TEST_CASE(test_time_duration) { static const boost::posix_time::ptime ref(boost::gregorian::date(1400,1,1)); static const boost::posix_time::ptime now(boost::gregorian::date(2010,5,18)); boost::int64_t elapsed = (now-ref).total_milliseconds(); boost::posix_time::time_duration d1 = boost::posix_time::millisec(elapsed); BOOST_CHECK_EQUAL(d1.total_milliseconds(), elapsed); } error in "test_time_duration": check d1.total_milliseconds() == elapsed failed [814839926290 != 19261584000000] This is caused by an overflow issue in the constructor of subsecond_duration (called by boost::posix_time::millisec): template<class base_duration, boost::int64_t frac_of_second> class subsecond_duration : public base_duration { public: typedef typename base_duration::traits_type traits_type; explicit subsecond_duration(boost::int64_t ss) : base_duration(0,0,0,ss*traits_type::res_adjust()/frac_of_second) {} }; Shouldn't this constructor check whether traits_type::res_adjust()>frac_of_second and then do “base_duration(0,0,0,ss*(traits_type::res_adjust()/frac_of_second))” (note the brackets)? Thanks, Johan _________________________________________________________________ http://clk.atdmt.com/UKM/go/195013117/direct/01/
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Johan Ditmar